Gear change control device and method

ABSTRACT

A gear change control device is provided for a straddle-type vehicle having a clutch and a transmission. The device includes a clutch actuator configured to engage and disengage the clutch. A transmission actuator is configured to change a gear of the transmission. At least one sensor is configured to sense an operational condition of the straddle type vehicle. At least one switch is configured to generate a gear change command. A controller is operatively connected to the clutch actuator, the transmission actuator, the at least one sensor, and the at least one switch. The controller is configured to change gears in response to the gear change command and during the gear change reengage the clutch under either a first control routine or second, different control routine based upon the operational condition of the straddle-type vehicle determined by the at least one sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.11/299,858, filed Dec. 12, 2005, which claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2004-359229, filed on Dec. 10,2004, the entire contents of both of which is expressly incorporated byreference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a device and method for controlling gearchanges, and more particularly, to a device and method for controllinggear changes in a straddle-type vehicle.

2. Description of the Related Art

Japanese patent publication JP-A-Hei 10-287150 describes a straddle-typevehicle (e.g., a motorcycle) that has a clutch and a transmission drivenby actuators (e.g., motors). Vehicles with such gear change controlsystems are increasingly popular. When a rider of such a straddle-typevehicle inputs a gear change command manually, the clutch and thetransmission in conjunction with each other automatically perform aseries of gear change operations. For example, a clutch actuatorautomatically disengages the clutch, a shift actuator automaticallyshifts up or down the transmission, and then the clutch actuatorautomatically reengages the clutch.

SUMMARY OF THE INVENTION

One aspect of the present invention is the realization that the gearchange control system described above is intended for changing gearswhile the vehicle is running. However, it is difficult to apply the samegear change control routine when the vehicle starts to run. That is,when the vehicle starts to run, the vehicle speed is not increasedenough and the rotational speed difference between the driving member(e.g., a friction disk for a wet multi-plate clutch) and the drivenmember (e.g., a clutch disk for a wet multi-plate clutch) of the clutchis often larger than during running conditions. Therefore, the gearchange control routine that is used while the vehicle is running willnot provide smooth gear changes when the vehicle starts to run. This mayimpair the riding comfort of the straddle-type vehicle.

Therefore, one object of the present invention is to provide a gearchange control device and method that can more smoothly changetransmission gears when the vehicle starts to run.

Accordingly, one aspect of the present invention comprises a gear changecontrol device for a straddle-type vehicle having a clutch and atransmission driven by respective actuators. The device includes meansfor engaging the clutch under a first control routine when thestraddle-type vehicle is starting to run with the clutch disengaged andthe transmission in gear. The device also includes means for determiningwhether a gear change command has been given to the transmission. Thedevice further includes means for, when a gear change command is given,causing the transmission to change gears according to the gear changecommand once the clutch is disengaged and then reengaging the clutchunder either the first control routine or a second control routine thatis different from the first control routine depending on a state of thestraddle-type vehicle.

Another aspect of the present invention comprises a method for operatinga straddle-type vehicle having a clutch and a transmission driven byrespective actuators, comprising. In the method, the clutch is engagedunder a first control routine when the straddle-type vehicle is beingstarted from a stopped condition in which the clutch is disengaged andthe transmission is in gear. It is determined whether a gear changecommand is given to the transmission. When a gear change command isgiven, the clutch is disengaged and the gears changed according to thegear change command once the clutch is disengaged. An operating state ofthe straddle-type vehicle is determined and, depending upon theoperating state, the clutch is reengaged under either the first controlroutine or a second control routine that is different from the firstcontrol routine.

Another aspect of the present invention is a gear change control devicethat is provided for a straddle-type vehicle having a clutch and atransmission. The device includes a clutch actuator configured to engageand disengage the clutch. A transmission actuator is configured tochange a gear of the transmission. At least one sensor is configured tosense an operational condition of the straddle type vehicle. At leastone switch is configured to generate a gear change command. A controlleris operatively connected to the clutch actuator, the transmissionactuator, the at least one sensor, and the at least one switch. Thecontroller is configured to change gears in response to the gear changecommand and during the gear change reengage the clutch under either afirst control routine or second, different control routine based uponthe operational condition of the straddle-type vehicle determined by theat least one sensor.

Another aspect of the present invention is a method for operating astraddle-type vehicle having a clutch and a transmission driven byrespective actuators. The method comprises determining whether a gearchange command is given to the transmission and, when a gear changecommand is given, disengaging the clutch, changing gears according tothe gear change command once the clutch is disengaged, determining anoperating state of the straddle-type vehicle; and depending upon theoperating state, reengaging the clutch under either the first controlroutine or a second control routine that is different from the firstcontrol routine.

For purposes of summarizing the invention, certain aspects, advantagesand novel features of the invention have been described herein. It is tobe understood that not necessarily all such advantages may be achievedin accordance with any particular embodiment of the invention. Thus, theinvention may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

A general structure that implements various features of specificembodiments of the invention will now be described with reference to thedrawings. The drawings and the associated descriptions are provided toillustrate embodiments of the invention and not to limit the scope ofthe invention.

FIG. 1 is a side elevational view of a motorcycle according to anembodiment of the present invention.

FIG. 2 is a schematic illustration of a gear change control deviceaccording to an embodiment of the present invention.

FIG. 3 is a schematic illustration of a group of sensors and switches ofthe gear change control device of FIG. 2.

FIG. 4 is a schematic illustration of a control routine that can beexecuted by the gear change control device of FIG. 2.

FIG. 5 is a schematic illustration of a control routine that can beexecuted by the gear change control device during normal conditions.

FIG. 6 a graphical illustration of a control routine that can beexecuted by the gear change control device during starting conditions.

FIG. 7 illustrates a clutch position table that can be referenced duringstarting conditions.

FIG. 8 is a graphical illustration of a control routine that can beexecuted by the gear change control device when shifting up duringrunning conditions.

FIG. 9 illustrates a clutch position table that can be referenced whenshifting up during running conditions.

FIG. 10 illustrates a clutch position change rate table that can bereferenced when shifting up during running conditions.

FIG. 11 is a graphical illustration of a shift up control routine thatcan be executed by the gear change control device during startingconditions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is an external side view of a motorcycle according to anembodiment of the present invention. In illustrated embodiment, themotorcycle 10 can include a front wheel 22 and a rear wheel 24.Handlebars 28, which can extend transversely with respect to the runningdirection of the vehicle 10, can be attached to a top or upper end of afront fork 30. The bottom or lower end of the front fork 30 can be, inturn, attached or coupled to the front wheel 22. A grip 12 and a clutchlever 14 can be attached or coupled to a first (e.g., left) end of thehandlebars 28 and an accelerator grip and a brake lever (not shown) canbe attached to the other (e.g., right) end of the handlebars 28.

With continued reference to FIG. 1, the motorcycle 10 can be providedwith a seat 32 that is positioned on an upper part of the motorcycle 10.The seat 32 can be configured such that a rider can straddle themotorcycle 10. Thus, the motorcycle 10 of FIG. 1 is a straddle-type,street vehicle, which includes a gear change control device and systemthat will be described in detail below. While the gear change controldevice and system has certain advantages in a street motorcycle, it isanticipated that the gear change control device and system describedherein can also be used in other types straddle-type vehicles includingbut not limited to other types of motorcycles (e.g., motorized bicyclesand scooters), all-terrain straddle-type vehicles, snowmobiles, etc. Inthese embodiments, the straddle-type vehicle may be driven by variousdrive devices, such as, for example, an internal combustion enginesengine, electric motors, and hybrids of both. The gear change controldevice and system described herein are particularly advantageous instraddle-type vehicles because they are generally lightweight and thuscan often gain significant vehicle speed during starting conditions(e.g., before the clutch is completely engaged). Therefore, it is highlyanticipated that gear change commands will be inputted during startingconditions. An advantage embodiments described herein is that the gearchange control system can appropriately respond to such gear changecommand inputs to suitably change transmission gears during startingconditions.

As shown in FIG. 1, the general construction of the illustratedmotorcycle 10 is similar to those of well-known street motorcycles.Thus, the illustrated embodiment can include a clutch actuator 18 thatcan be installed above an engine 16 of the motorcycle 10 below a fueltank 26. The actuator 18 can be configured to actuate (e.g., through amotor) a clutch provided in a crankcase of the engine 16. A shiftactuator 20 can be provided to actuate (e.g., through a motor) atransmission provided in a transmission case of the engine 16. Theoperation of the clutch actuator 18 is controlled by a gear changecontrol device or system 40 (see FIG. 2) to engage and disengage theclutch. The shift actuator 20 is also controlled by the control device40 to shift the transmission. The clutch lever 14 is operativelyconnected to the clutch actuator 18 through, for example, a wire orother transmission device so that the clutch can also be engaged anddisengaged through the clutch lever 14.

FIG. 2 is a schematic illustration of an embodiment of the gear changecontrol device 40 of the motorcycle 10. As shown in FIG. 2, a group ofsensors and switches 62, the clutch actuator 18, and the shift actuator20 can be operatively connected to the control device 40 A battery 54can also be operatively connected to the control device 40 to supplyelectric power to the control device 40. The electric power can also besupplied to the clutch actuator 18 and the shift actuator 20 via thecontrol device 40 as will be described below. The electric power can beused to operate the control device 40, as well as the clutch actuator 18and the shift actuator 20.

In this application, various components are described as being“operatively connected” to the control unit. It should be appreciatedthat this is a broad term that includes physical connections (e.g.,electrical wires) and non-physical connections (e.g., radio or infraredsignals). It should also be appreciated that “operatively connected”includes direct connections and indirect connections (e.g., through anadditional intermediate device).

In the illustrated embodiment, the clutch actuator 18 can include a DCmotor for disengaging the clutch by forward drive of the DC motor andreengaging the clutch by reverse drive, and setting the clutch positionto any state between the engaged state and the disengaged state. Theclutch actuator 18 can be provided with a clutch potentiometer 18 a,that comprises, for example, a resistor or another suitable device, forapplying a voltage indicating the state of the clutch actuator 18, or avoltage indicating the clutch position, to the control device 40. Thevoltage value can be used by the control device 40 to indicate clutchposition. The motorcycle 10 can include one clutch for preventing therotational driving force of the engine 16 from not being inputted to thetransmission when both starting to run and shifting the transmission.

The shift actuator 20 can also include a DC motor for shifting up byforward drive of the DC motor and shifting down by reverse drive. Theshift actuator 20 can be attached to a shift arm of the transmission.The DC motor can rotate the shift arm in one direction by forward driveand in the opposite direction by reverse drive. The shift actuator 20can be provided with a shift potentiometer 20 a, which comprises aresistor or the like, for applying a voltage indicating the state of theshift actuator 20, or a voltage indicating the rotation angle of theshift arm, to the control device 40. The voltage value can be used bythe control device 40 for indicating rotation angle. The transmissioncan be configured in a variety of ways and, in one embodiment, caninclude neutral and first to fifth gear positions and can be aconventional type of transmission (e.g., a dog transmission).

As shown in FIG. 3, the group of sensors and switches 62 can include anaccelerator sensor 62 a, a foot brake sensor 62 b, a hand brake sensor62 c, a gear position sensor 62 d, a key switch sensor 62 e, a vehiclespeed sensor 62 f, driving side clutch rotational speed sensor 62 g, adriven side clutch rotational speed sensor 62 h, a shift up switch 62 i,and a shift down switch 62 j. The accelerator sensor 62 a can beconfigured to detect the accelerator opening and to input relevant datato the control device 40. The foot brake sensor 62 b can be configuredto input to the control device 40 data indicating the depression angleof a rear wheel brake attached to the rear wheel 24 and/or whether ornot the rear wheel brake is depressed. The hand brake sensor 62 c can beconfigured to input to the control device 40 data indicating theoperation amount of a front wheel brake attached to the front wheel 22and/or whether or not the front wheel brake is operated. The gearposition sensor 62 d can be attached to the transmission and can beconfigured to input to the control device 40 data indicating the currentgear position (e.g., a rotation amount of a shift drum). The key switchsensor 62 e can be configured to detect the state of a key switch (e.g.,on or off, or the like) and can be configured to input relevant data tothe control device 40.

The vehicle speed sensor 62 f can be configured detect the vehicle speed(or equivalent information) and to input relevant data to the controldevice 40. The vehicle speed sensor 62 f can be configured to detect thevehicle speed by detecting the rotational speed of a drive shaft (orcountershaft) of the transmission or the amount of movement of acomponent coupled to the drive shaft (preferably without play) such as achain, a shaft drive section, or a tire wheel. The vehicle speed sensor62 f may also be configured to obtain the vehicle speed by detecting therotational speed of a middle shaft (e.g., idler shaft) of thetransmission and multiplying the detected value by the speed reductionratio corresponding to the current gear position of the transmission.

The driving side clutch rotational speed sensor 62 g can be configuredto detect the rotational speed of a driving member of the clutch and toinput relevant data to the control device 40. In one embodiment, theclutch is a wet multi-plate type of clutch. In such an embodiment, thedriving member (from which rotational speed can be detected by thedriving side clutch rotational speed sensor 62 g) can be a frictiondisk, for example. In turn, the driven side clutch rotational speedsensor 62 h can be configured to detect the rotational speed of a drivenmember (e.g., a follower member) of the clutch and to input relevantdata to the control device 40. In an embodiment that utilizes awet-multi-plate type of clutch, the driven member (from which rotationalspeed can be detected by the driven side clutch rotational speed sensor62 h) is a clutch disk, for example. The control device 40 can beconfigured to compute the difference between the rotational speedsinputted from the driving and driven side clutch rotational speedsensors 62 g, 62 h and to use the computed difference as a clutchrotational speed difference to control the clutch actuator 18 as will bedescribed below. In some embodiments, instead of the driving side clutchrotational speed sensor 62 g, a sensor configured for detecting therotational speed of the engine 16 (e.g., a crankshaft sensor) or themiddle shaft may be provided. In such embodiments, the rotational speedof the friction disk can be obtained by multiplying the detectionresults by the sensor by a predetermined speed reduction ratio. When thetransmission is not in neutral, the rotational speed of the clutch diskcan be obtained by dividing the rotational speed of the drive shaft orthe amount of movement of a component coupled to the drive shaft withoutplay such as a chain, a shaft drive section, or a tire wheel by thespeed reduction ratio corresponding to the current gear position.

The shift up switch 62 i can be provided in the vicinity of the grip 12of the handlebars 28. In one embodiment, when the rider presses down onthe shift up switch 62 i, a shift up command (i.e., a gear changecommand) is inputted to the control device 40. The shift down switch 62j can also be provided in the vicinity of the grip 12 of the handlebars28. In one embodiment, when the rider presses down on the shift downswitch 62 j, a shift down command (i.e., a gear change command) isinputted to the control device 40. Of course those of skill in the artwill recognized that the shift up and shift down switches 62 i, j can bearranged in different manners give the goal of providing a device thatthe rider can actuate to indicate a desire to switch gears up and/ordown. For example, the up and down switches 62 i, j can be combined intoa single device (e.g., lever or knob) and/or comprise a different typeof actuator (e.g., buttons, levers, etc.).

With reference back to FIG. 2, the control device 40 is a feedbackcontrol device that can include of one or more hard-wired circuits,dedicated processors and memory, and/or a general purpose processor andmemory running one or a plurality of control programs. In theillustrated embodiment, the control device 40 includes a mainmicrocomputer 46, which can utilize or calculate various control maps orformulas (e.g., correlations of reference control signals to variousoperating conditions of the engine or other fundamental engine controldata) that may be stored in advance in a storage device (e.g., ROM). Forexample, as will be explained in detail below, the microcomputer 46 canbe configured to control the operation of the clutch actuator 18 and theshift actuator 20 based on the various information indicating the stateof the vehicle inputted from the group of sensors and switches 62, theclutch potentiometer 18 a, and the shift potentiometer 20 a. For easierunderstanding, the control device 40 and its components will bedescribed as if they discriminate and substantial units. However, inmodified embodiments, the control device 40 and/or its components can bepart other control systems of the motorcycle 10. In addition, variouscomponents, functions and aspects of the control device 40 and itscomponents may be grouped and/or separated into sub-devices or separatedevices.

The components of the control device 40 will now described in moredetail. With reference to the illustrated embodiment of FIG. 2, thecontrol device 40 includes the main microcomputer 46, a power supplycircuit 48, a motor drive circuit 42 configured to drive the clutchactuator 18, and a motor drive circuit 44 configured to drive the shiftactuator 20.

The power supply circuit 48 can include a switch (not shown), whichturns on in conjunction with the key switch and a self-holding circuit48 a. When the switch turns on, the power supply circuit 48 can covert avoltage of a battery 54 into a driving voltage for the mainmicrocomputer 46 and can start applying the converted voltage to themain microcomputer 46. Even after the key switch is turned off, theswitch can be held on by the self-holding circuit 48 a. Until the mainmicrocomputer 46 is completely shut down, the power supply circuit 48can continue to apply the driving voltage. When the shutdown process iscomplete, the main microcomputer 46 can command the self-holding circuit48 a to stop the power supply. Then, the power supply circuit 48 canstop the power supply to the main microcomputer 46.

The motor drive circuit 42 can include a known-type H-bridge circuit oranother appropriate circuit. The motor drive circuit 42 can beconfigured to supply a current from the battery 54 to the DC motor,which causes the clutch actuator 18 to rotate in a direction and at arate in accordance with a clutch actuator drive signal supplied from themain microcomputer 46. The motor drive circuit 44 can also include aknown-type H-bridge circuit or another appropriate circuit. The motordrive circuit 52 is configured to supply a current from the battery 54to the DC motor, which causes the shift actuator 20 to rotate in adirection and at a rate in accordance with a shift actuator drive signalsupplied from the main microcomputer 46.

As mentioned above, the main microcomputer 46 can comprise a known-typecomputer and is configured to control the operation of the clutchactuator 18 and the shift actuator 20 based on the various informationindicating the state of the vehicle inputted from the group of sensorsand switches 62, the clutch potentiometer 18 a, and the shiftpotentiometer 20 a as described above. The main microcomputer 46 canalso be configured to execute the shutdown process after the key switchis turned off, and commands the self-holding circuit to stop the powersupply when the shutdown process is finished.

With reference to FIGS. 4-11, a gear change control routine which can beexecuted by the gear change control device 40 will now be describe. Inone embodiment, the routine provides for engaging the clutch under afirst control routine when the straddle-type vehicle is being startedfrom a stopped or stopping condition. In such an embodiment, if a gearchange command is given while the clutch is being engaged to start thestraddle-type vehicle to run, or in other words before the clutch iscompletely engaged, the clutch is engaged and the transmission is causedto change gears. Then, the clutch is reengaged under either the firstcontrol routine or a second control routine, depending on the vehiclestate. The vehicle state can be the rotational speed difference betweenthe driving member and the driven member of the clutch, the speed of thestraddle-type vehicle, the output of a drive source provided in thestraddle-type vehicle (such as engine speed), and/or other relevantparameters. According to one embodiment, if a gear change command isgiven while the vehicle is starting to run, the clutch is reengagedunder either the control routine (or substantially similar controlroutine) that was initially used to start the vehicle to run (i.e., thefirst control routine) or different control from the former, dependingon the vehicle state. Therefore, the clutch can be reengaged smoothlyaccording to the vehicle state.

With reference to illustrated embodiment, FIG. 4 is a control statetransition diagram illustrating an embodiment of a control method thatcan be executed by the control device 40 when a main key is turned onand off. As shown in the drawing, the main microcomputer 46 can beconfigured to execute a shutdown time control program 100, a clutch offcontrol program 102, a clutch on control program 104, a shutdown program106, a startup program 108, and a startup time control program 110.These programs can be stored beforehand in a ROM (information storagemedium) included in the main microcomputer 46.

The shutdown time control program 100 can be executed when data inputtedfrom the key switch sensor 62 e indicates that a key switch 60 has beenturned off. If the gear is in and the clutch is on, the clutch offcontrol program 102 is started up. The clutch off control program 102makes the clutch disengage and then the shutdown time control program100 resumes its control. The term “the gear is in” refers to a statewhere the transmission of the motorcycle 10 is engaged in any gearposition, or in other words an occasion where data inputted from thegear position sensor 62 d indicates that the transmission is set to anyof the first to fifth gear positions, for example, (i.e., gearspositions other than neutral). The term “the clutch is on” refers to anoccasion where clutch position data obtained from on the output from theclutch potentiometer 18 a indicates that the clutch is engaged (i.e.,the clutch is on).

If the gear is in and “the clutch is off” and “the vehicle is stopping”or if neutral and the clutch is off, the shutdown time control program100 can execute the clutch on control program 104. The clutch on controlprogram 104 controls the clutch to be engaged and then the shutdownprogram 106 is subsequently executed. The term “the clutch is off”refers to a condition where clutch position data obtained from theoutput from the clutch potentiometer 18 a indicates that the clutch isdisengaged (i.e., the clutch is off). The term “the vehicle is stopping”refer to a condition where vehicle speed data inputted from the vehiclespeed sensor 62 f continues to indicate a predetermined speed (e.g., 3km per hour) or lower for a predetermined period (e.g., 3 seconds) orlonger or some other indication that the vehicle is stopping. The term“neutral” refers to a condition where data inputted from the gearposition sensor 62 d indicates that the transmission of the motorcycle10 is in a neutral position.

With continued reference to FIG. 4, the shutdown time control program100 can also start up the shutdown program 106 if the motorcycle 10 isin neutral and the clutch is on. However, if data that indicates the keyswitch 60 has been turned on are inputted during the shutdown timecontrol, the startup program 108 is executed.

The clutch off control program 102 supplies a clutch actuator drivesignal of a predetermined pattern to the motor drive circuit 42 todisengage the clutch by forward rotation of the DC motor 18 a of theclutch actuator 18. On the other hand, the clutch on control program 104supplies a clutch actuator drive signal of a predetermined pattern tothe motor drive circuit 42 to engage the clutch by reverse rotation ofthe DC motor 18 b.

The shutdown program 106 can stop the operation of the mainmicrocomputer 46. Here, the shutdown program 106 can supply a commandsignal to stop the power supply to the self-holding circuit 48 a. Thiscan allow the power supply circuit 48 to stop the power supply to themain microcomputer 46.

The startup program 108 can be executed when a key to the motorcycle 10is inserted into the key switch 60 and turned on while the vehicle isstopping or while the shutdown time control program 100 is beingexecuted. Whether or not the key is inserted into the key switch 60 andturned on can be determined based on the output from the key switchsensor 62 e. The startup program 108 can initialize the components ofthe control device 40 and can determine whether or not the transmissionof the motorcycle 10 is in neutral. If the motorcycle is in neutral, thecontrol proceeds to normal control (e.g., the stopping state program 202shown in FIG. 5). If the transmission of the motorcycle 10 is in gear atstartup, the startup program 108 starts up the startup time controlprogram 110. The startup time control program 110 monitors whether ornot the brake is operated, and when the brake is operated (i.e., thebrake in on), starts up the clutch off control program 102. When theclutch is disengaged, the startup time control program 110 resumes itscontrol. If the gear is in and the clutch is off, the control proceedsto the normal control (e.g., the stopping state program 202 shown inFIG. 5). Whether or not the brake is operated can be determined based onthe input from the foot brake sensor 62 b and the hand brake sensor 62c. For example, the brake is determined to be in operation when datainputted from the foot brake sensor 62 b indicates that the rear wheelbrake is in operation or when data inputted from the hand brake sensor62 c indicate that the front wheel brake is in operation. For example,the brake of the motorcycle 10 is determined to be in operation wheneither the front wheel brake or the rear wheel brake is in operation.However, the brake of the motorcycle 10 can be determined to be inoperation only when both the brakes are in operation.

FIG. 5 is a control state transition diagram illustrating an embodimentof the normal control of the motorcycle 10. The main microcomputer 46can execute the control method graphically shown in FIG. 5 when the“main key on” step shown in FIG. 4 is finished. As shown in FIG. 5, themain microcomputer 46 can be configured to execute gear change controlprograms 200U, 200D, 206U, and 206D, the stopping state program 202, astarting-to-run control program 204, and a running state program 208.These programs can also stored beforehand in the ROM (informationstorage medium) included in the main microcomputer 46. The normalcontrol of the control device 40 has a stopping mode, a starting-to-runmode, and a running mode. The stopping mode is controlled by thestopping state program 202 and the gear change control programs 200U and200D. The starting-to-run mode is controlled by the starting-to-runcontrol program 204. The running mode is controlled by the running stateprogram 208 and the gear change control programs 206U and 206D.

The stopping state program 202 can start to control the vehicle inresponse to a command from the startup program 108, the startup timecontrol program 110, the gear change control programs 200U and 200D, andthe running state program 208. The stopping state program 202 canmaintain the state of the transmission and the clutch. When the shift upswitch 62 i is determined to be pressed with the transmission set inneutral, the control can proceed (preferably immediately) to the gearchange control program 200U (see arrow 218). When the shift down switch62 j is determined to be pressed with the transmission set in any of thefirst to fifth gear positions (for example), the control can proceed(preferably immediately) to the gear change control program 200D (seearrow 220). If it is determined that the engine speed is a predeterminedvalue n3 (see FIG. 7) or higher, the transmission can be set in any ofthe first to fifth gear positions (for example), and if the vehiclestate does not meet starting-to-run prohibition conditions, the controlproceeds (preferably immediately) to the starting-to-run control program204 (arrow 214).

The starting-to-run prohibition conditions can be as follows: 1) thevehicle running speed is maintained at a predetermined speed (forexample, 3 km/h) or lower for a predetermined period (for example, 3seconds) or longer with the transmission set in the third gear positionor higher (i.e., the vehicle is determined to stop running with thetransmission in the third gear position or higher); or 2) thetemperature of the coolant of the engine 16 is at a predeterminedtemperature (for example, 40° C.) or lower and the accelerator openingindicated by the accelerator sensor 62 a is a predetermined opening orsmaller (i.e., the vehicle is determined to be at first idle).

The gear change control program 200U controls to disengage (i.e., offposition) the clutch if the clutch is engaged (i.e., on position) andshift up the transmission by one gear position. For example, a clutchactuator drive signal of a predetermined pattern can be supplied to themotor drive circuit 42 to drive the clutch actuator 18. As a result, theclutch can be disengaged. Also, a shift actuator drive signal of apredetermined pattern can be supplied to the motor drive circuit 44 todrive the shift actuator 20. As a result, the transmission can beshifted. When the gear change control program 200U finishes the controlas described above (clutch off and shift up), the control can proceed tothe stopping state program 202 (see arrow 216).

In the same or similar manner, the gear change control program 200D cancontrol to disengage (move to off position) the clutch if the clutch isengaged (in the on position) and shift down the transmission by one gearposition. When this control (clutch off and shift down) is finished, thecontrol can proceed to the stopping state program 202 (see arrow 222).

The starting-to-run control program 204 can start to control the vehiclein response to a command from the stopping state program 202. Thestarting-to-run control program 204 can execute starting-to-run control,for example, by obtaining the engine speed and driving the clutchactuator 18 to attain a clutch position in accordance with the obtainedengine speed. For example, the main microcomputer 46 can reference atable where clutch positions of the clutch are correlated with theengine 16 speeds (see FIGS. 6 and 7) to set the clutch position inaccordance with the engine 16 speed. During the starting-to-run control,if the engine speed is determined to have fallen to a predeterminedvalue n′ (n′<n3) or lower, the control can proceed (preferablyimmediately) to the stopping state program 202 (see arrow 238). When theshift up switch 62 i is pressed down during the starting-to-run control,if it is determined that the transmission is set in any of the first tofourth gear positions and the clutch rotational speed difference is apredetermined value Δn (Δn can be a value at which substantially noshock occurs when the clutch is engaged under second control routine,e.g., half clutch control in changing gear positions during the normalrunning) or larger, the control proceeds (preferably immediately) to thegear change control program 200U (see arrow 212).

When the shift down switch 62 j is pressed down during thestarting-to-run control, if it is determined that the transmission isset in any of the second to fifth gear positions and the clutchrotational speed difference is the predetermined value Δn or higher, thecontrol can proceed (preferably immediately) to the gear change controlprogram 200D (see arrow 226). When the shift up switch 62 i is presseddown during the starting-to-run control, if it is determined that thetransmission is set in any of the first to fourth gear positions and theclutch rotational speed difference is smaller than the predeterminedvalue Δn, the control can proceed (preferably immediately) to the gearchange control program 206U (see arrow 240). When the shift down switch62 j is pressed down during the starting-to-run control, if it isdetermined that the transmission is set in any of the second to fifthgear positions and the clutch rotational speed difference is smallerthan the predetermined value Δn, the control can proceed (preferablyimmediately) to the gear change control program 206D (see arrow 230). Ifthe clutch rotational speed difference has converged to a predeterminedvalue Δn′ (Δn′ is a value at which substantially no shock occurs whenthe clutch is engaged (for example, 50 rpm)) or lower during thestarting-to-run control, the control can proceed (preferablyimmediately) to the running state program 208 (see arrow 236).

The running state program 208 can start to control the vehicle inresponse to a command from the starting-to-run control program 204 andthe gear change control programs 206U and 206D. The running stateprogram 208 can maintain the state of the transmission and the clutchand can rotate the engine 16 according to the accelerator openingdetected by the accelerator sensor 62 a to run the motorcycle 10. Atthis time, when the shift up switch 62 i is pressed down, if it isdetermined that the transmission is set in any of the first to fourthgear positions and the engine speed after shifting up will be apredetermined lower limit engine speed (i.e., under-rev speed) orhigher, the control can proceed (preferably immediately) to the gearchange control program 206U (see arrow 242). When the shift down switch62 j is pressed down, if it is determined that the transmission is setin any of the second to fifth gear positions and the engine speed aftershifting down will be a predetermined upper limit engine speed (i.e.,over-rev speed) or lower, the control can proceed (preferablyimmediately) to the gear change control program 206D (see arrow 232).When the engine speed falls down to a predetermined value n″ (n″<n3) orlower with the transmission set in any of the first to fifth gearpositions, the control can proceed to the stopping state program 202(see arrow 228).

The gear change control program 206U can start to control the vehicle inresponse to a command from the running state program 208 and thestarting-to-run control program 204. The gear change control program206U can execute a shift up control, that is, drives the clutch actuator18 to disengage the clutch, drive the shift actuator 20 to shift up thetransmission, and then drive the clutch actuator 18 to reengage theclutch. In reengaging the clutch, a table where rates at which theclutch position is changed are correlated with the rotational speeddifferences between the driving member and the driven member of theclutch (see FIGS. 10 and 11) can referenced to change the clutchposition at a rate in accordance with the rotational speed differencebetween the driving member and the driven member of the clutch (the gearchange control program 206D can be executed in the same or similarmanner). When the shift up control is finished, the control can proceedto the running state program 208 (see arrow 244). However, when thevehicle speed of the motorcycle 10 falls down to a predetermined speedor lower in particular during the shift up control, for example, thecontrol can proceed to the gear change control program 200U (see arrow210).

The gear change control program 206D can start to control the vehicle inresponse to a command from the running state program 208 or thestarting-to-run control program 204. The gear change control program206D can execute a shift down control, that is, drive the clutchactuator 18 to disengage the clutch, drive the shift actuator 20 toshift down the transmission, and then drive the clutch actuator 18 toreengage the clutch. When the series of control is finished, the controlcan proceed to the running state program 208 (see arrow 234). However,when the vehicle speed of the motorcycle 10 falls down to apredetermined speed or lower during the shift down control, for example,the control can proceeds to the gear change control program 200D (seearrow 224).

The vehicle control configured as described above can suitably controlgear changes (i.e., control the transmission and the clutch) accordingto various running operation states of the motorcycle 10. Although notshown in FIG. 4 or 5, the main microcomputer 46 can have a residentprogram for determining and dealing with an abnormality so thatabnormalities of the vehicle can be properly handled.

A description the starting-to-run control, the gear change control(i.e., shift up control) during running, and the gear change controlduring starting-to-run will now be provided.

With reference to FIG. 6, the starting-to-run control for the motorcycle10 is shown graphically. FIG. 6 shows the transition of the state of themotorcycle 10 by the starting-to-run control. Specifically, FIG. 6( a)shows the transition of the clutch position over time, from thebeginning to the end of the starting-to-run control and FIG. 6( b) showsthe transition of the rotational speeds of the driving member and thedriven member of the clutch over time, from the beginning to the end ofthe starting-to-run control. As shown in these drawings, when thecontrol proceeds from the stopping state program 202 to thestarting-to-run control program 204 and thus the control mode proceedsfrom the stopping mode to the starting-to-run mode, the clutch positioncan be controlled according to the table shown in FIG. 7. That is, theclutch position in accordance with the engine speed can be obtained fromthe table shown in FIG. 7 at predetermined intervals, and the clutchactuator 18 can be controlled to attain the obtained clutch position.When the clutch rotational speed difference converges to thepredetermined value Δn′ or smaller, the clutch can be engaged at aconstant rate.

In the table used in the starting-to-run control shown in FIG. 7, theengine speed and the clutch position can be correlated (n1<n2<n3<n4<n5;c1<c2<c3<c4<c5). In the table, the engine speed lower than n1 can becorrelated with the clutch position c5 (e.g., the clutch completelyoff). The engine speed that is greater than n1 but lower than n3 can becorrelated with the clutch positions c4 and c5. In this case, either ofthe clutch positions can be selected according to the starting-to-runpreparation start conditions and the starting-to-run cancel conditionsto be described later. The clutch position c4 can be set within a rangewhere the driving force of the engine 16 is not transmitted to the rearwheel 24.

The engine speed not lower than n3 but lower than n4 can be correlatedto the range of the clutch positions c4 through c3. A higher enginespeed can be correlated to a clutch position with a smaller value (anarrower clutch position). The engine speed greater than n4 but lowerthan n5 can be correlated to the range of the clutch positions c3through c2. A higher engine speed can be correlated to a clutch positionwith a smaller value. Lastly, the engine speed higher than n5 can becorrelated to the clutch position c1 with the smallest value (the clutchcompletely on). This can be for engaging the clutch securely in the highspeed range. The table shown in FIG. 7 can allow the clutch position tobe set to a value in accordance with the engine speed during thestarting-to-run control, and thereby allows the vehicle to start to runsmoothly.

Description will now be made of the starting-to-run preparation startconditions and the starting-to-run preparation cancel conditions. Thestarting-to-run preparation start conditions can be as follows: a1) thetransmission is set to a predetermined gear which permits starting torun (for example, the first gear and the second gear) and the enginespeed is the predetermined value n3 (see FIG. 7) or higher; or a2) theengine speed is the predetermined value n1 (see FIG. 7) or higher andthe accelerator opening is a predetermined amount or larger. When theengine speed is greater than n1 but lower than n3, if either of theabove conditions a1 or a2 is satisfied, the clutch position c4 can beused. This can allow the vehicle to start to run immediately. The abovecondition a2 can require the accelerator opening to be a predeterminedamount or larger, and thus can achieve smoother control. On the otherhand, the starting-to-run preparation cancel conditions can be asfollows: b1) the engine speed is lower than the predetermined value n2(see FIG. 7) and the accelerator opening is smaller than a predeterminedamount; or b2) the engine speed is lower than the predetermined value n1(see FIG. 7). When the engine speed is greater than n1 but lower thann3, if either of the above conditions b1 or b2 is satisfied, the clutchposition c5 can be used. Again, the above condition b1 can require theaccelerator opening to be a predetermined amount or smaller, and thuscan achieve smoother control.

The starting-to-run control as described above can securely and smoothlyengage the clutch when the vehicle starts to run where the clutchrotational speed difference is large, by securely narrowing the distancebetween the clutch members as the engine speed increases.

Next, description is made of the gear change control (shift up control)while the motorcycle 10 is running. As described above, this control canbe executed by the gear change control program 206U. FIG. 8 shows thetransition of the vehicle state over time during the shift up control(e.g., from the first gear to the second gear). FIG. 8( a) shows thetransition of the clutch position over time. FIG. 8( b) shows thetransition of the shift actuator rotational angle (or the shift armrotational angle) over time. FIG. 8( c) shows the transition of the gearposition outputted from the gear position sensor 62 d over time. Asshown in these drawings, when a shift up command is given (timing t1 inthe drawing), the clutch actuator 18 can disengage the clutch at aconstant rate. When a predetermined waiting period T elapses from thetiming t1, the shift actuator 20 can be driven in the shift updirection. Then, when it is detected that the intended gear position isreached (timing t2 in the drawing), half clutch control can start. Forexample, the clutch position is set to a value in accordance with theclutch rotational speed difference at the timing t2 (initial value)according to the table shown in FIG. 9. In the table shown in FIG. 9,the clutch rotational speed difference and the initial value of theclutch position can be correlated. The gear change control program 206Umonitors the timing at which the clutch position reaches the initialvalue obtained from this table. When the clutch position reaches theinitial value (timing t3 in the drawing), then the clutch positionchange rate in accordance with the clutch rotational speed differencecan be obtained according to the table shown in FIG. 10 at predeterminedintervals, and the clutch position can be changed (i.e., the clutchposition is narrowed) at the obtained change rate. Also, the shiftactuator 20 can be returned to its initial position at the timing t3.

The gear change control as described above can determine the clutchposition in accordance with the clutch rotational speed differenceduring gear changes, and thus can change gears immediately duringrunning.

Description will now be made of the gear change control where a shift upis performed when the motorcycle 10 starts to run. The starting-to-runcontrol program 204 can make the motorcycle 10 start, which has beenstationary with the clutch disengaged and the transmission in gear, torun by engaging the clutch under the above starting-to-run control (seeFIG. 6). The starting-to-run control program 204 can also determineswhether or not a shift up or shift down command is given to thetransmission while the clutch is half engaged. If it is determined thata shift up command is given while the clutch is being engaged, either ofthe following controls can be performed depending on the state of themotorcycle 10: U1) the gear change control program 200U once disengagesthe clutch and causes the transmission to change gears according to theshift up command, and the starting-to-run control program 204 reengagesthe clutch (arrows 212, 216, and 214); or U2) the gear change controlprogram 206U once disengages the clutch and causes the transmission tochange gears according to the shift up command, and the clutch isreengaged under control different from the predetermined starting-to-runcontrol described above (arrow 240).

On the other hand, if it is determined that a shift down command isgiven while the clutch is being engaged, either of the followingcontrols can be performed depending on the state of the motorcycle 10:D1) the gear change control program 200D once disengages the clutch andcauses the transmission to change gears according to the shift downcommand, and the starting-to-run control program 204 reengages theclutch (arrows 226, 222, and 214); or D2) the gear change controlprogram 206D once disengages the clutch and causes the transmission tochange gears according to the shift up command, and the clutch isreengaged under control different from the predetermined starting-to-runcontrol described above (arrow 230).

FIG. 11 shows the transition of the vehicle state over time when a shiftup command is given during the starting-to-run control and the controlof U1 above is executed. FIG. 11( a) shows the transition of the clutchposition over time. FIG. 11( b) shows the transition of the shiftactuator rotational angle (or the shift arm rotational angle) over time.FIG. 11( c) shows the transition of the gear position outputted from thegear position sensor 62 d over time. As shown in these drawings, whenthe starting-to-run control program 204 starts the starting-to-runcontrol and a shift up command is inputted from the shift up switch 62 iduring the starting-to-run control, the clutch rotational speeddifference and the gear position can be obtained. If it is determinedthat the transmission is set in any of the first to fourth gearpositions and the clutch rotational speed difference is thepredetermined value Δn or smaller, the control can proceed (preferablyimmediately) to the gear change control program 200U (see arrow 212).

The gear change control program 200U can drive (preferably immediately)the clutch actuator 18 to set the clutch to a clutch position CA whichis a predetermined amount Δ displaced in the clutch engaging directionfrom a clutch position CB where the clutch is completely disengaged. Thegear change control program 200U can also drive the shift actuator 20 tocause the transmission to change gears (shift up). When the shift up iscompleted, the gear change control program 200U can return the shiftactuator 20 to its initial position, and the control can proceed to thestopping state program 202 (see arrow 216). If the stopping stateprogram 202 determines that the engine speed is the predetermined valuen3 (see FIG. 7) or higher, the transmission is set in any of the firstto fifth gear positions, and the vehicle state does not meet thestarting-to-run prohibition conditions, the control can proceed(preferably immediately) to the starting-to-run control program 204 (seearrow 214). Then, the starting-to-run control program 204 can reengagethe clutch using the tables of FIGS. 6 through 7.

When a shift up command is inputted during the starting-to-run control,if it is determined that the transmission is set in any of the first tofourth gear positions and the clutch rotational speed difference issmaller than the predetermined value Δn, the control can proceed fromthe starting-to-run control program 204 to the gear change controlprogram 206U (arrow 240). The change gear control is executed using thetables of FIG. 8 through FIG. 10.

The gear change control system as described above advantageouslyexecutes different clutch controls depending on the clutch rotationalspeed difference when a gear change operation is performed using theshift up switch 62 i or the shift down switch 62 j during thestarting-to-run control by the starting-to-run control program 204.Therefore, the system can achieve clutch engagement suitable for thevehicle state, thereby improving the riding comfort of the motorcycle10.

For purposes of summarizing the invention, certain aspects, advantagesand novel features of the invention have been described herein. It is tobe understood that not necessarily all such advantages may be achievedin accordance with any particular embodiment of the invention. Thus, theinvention may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

The above-described systems and methods can also be used with othertypes of transmissions, clutch mechanisms and associated control systemsand routines, such as those described in one or more of the followingcopending United States Patent Applications: (1) application Ser. No.11/301,282, filed on Dec. 12, 2005, which is entitled STRADDLE-TYPEVEHICLE HAVING CLUTCH CONTROL DEVICE AND METHOD OF USING CLUTCH CONTROLDEVICE and which has Attorney Docket No. FY.52014US0A; (2) applicationSer. No. 11/301,288, filed on Dec. 12, 2005, which is entitledSTRADDLE-TYPE VEHICLE HAVING CLUTCH ENGAGEMENT CONTROL DEVICE AND METHODOF USING CLUTCH ENGAGEMENT CONTROL DEVICE and which has Attorney DocketNo. FY.52015US0A; (3) application Ser. No. 11/301,646, filed on Dec. 12,2005, which is entitled CLUTCH ACTUATOR FOR STRADDLE-TYPE VEHICLE andwhich has Attorney Docket No. FY.52018US0A; and (4) application Ser. No.11/299,720, filed on Dec. 12, 2005, which is entitled APPARATUS ANDMETHOD FOR CONTROLLING TRANSMISSION OF STRADDLE-TYPE VEHICLE and whichhas Attorney Docket No. FY.52017US0A. The contents of all of theabove-noted copending U.S. patent applications are hereby incorporatedby reference in their entireties.

In addition, although this invention has been disclosed in the contextof certain preferred embodiments and examples, it will be understood bythose skilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. For example, various methods comprising one or more steps andprocedures have been described. However, it should be appreciated thatin modified embodiments, the order of these steps and procedures can bechanged and/or one or more steps and procedures can be combined,eliminated and/or subdivided. In addition, while a number of variationsof the invention have been shown and described in detail, othermodifications, which are within the scope of this invention, will bereadily apparent to those of skill in the art based upon thisdisclosure. It is also contemplated that various combinations orsubcombinations of the specific features and aspects of the embodimentsmay be made and still fall within the scope of the invention.Accordingly, it should be understood that various features and aspectsof the disclosed embodiments can be combine with or substituted for oneanother in order to form varying modes of the disclosed invention. Thus,it is intended that the scope of the present invention herein disclosedshould not be limited by the particular disclosed embodiments describedabove, but should be determined only by a fair reading of the claimsthat follow.

1. A gear change control device for a straddle-type vehicle having aclutch and a transmission driven by respective actuators, comprising:means for engaging the clutch under a first control routine, when thestraddle-type vehicle is stopped with the clutch disengaged and thetransmission in gear; means for determining whether a gear changecommand has been given to the transmission while the clutch is beingengaged; and means for, when a gear change command is given while theclutch is being engaged, causing the transmission to change gearsaccording to the gear change command once the clutch is disengaged andthen reengaging the clutch under either the first control routine or asecond control routine that is different from the first control routinedepending on a state of the straddle-type vehicle.
 2. The gear changecontrol device according to claim 1, comprising means for engaging theclutch under the first control routine when the rotational speeddifference between a driving member and a driven member of the clutch isequal to or greater than a predetermined value, and means for engagingthe clutch under the second control routine when the rotational speeddifference between the driving member and driven member of the clutch isless than the predetermined value.
 3. The gear change control deviceaccording to claim 1, wherein the state of the straddle-type vehiclecomprises a rotational speed difference between a driving member and adriven member of the clutch.
 4. The gear change control device accordingto claim 1, wherein the first control routine comprises instructions toreengage the clutch by changing a position of the clutch as a functionof an engine speed of an engine mounted on the straddle type vehicle. 5.The gear change control device according to claim 4, wherein the firstcontrol routine comprises instructions to reference a table thatcorrelates clutch position with the engine speed.
 6. The gear changecontrol device according to claim 1, wherein the second control routinecomprises instructions to reengage the clutch by changing the clutchposition at a rate which is determined by a rotational speed differencebetween a driving member and a driven member of the clutch.
 7. The gearchange control device according to claim 6, wherein the second controlroutine comprises instructions to reference a table where the rate whichthe clutch position of the clutch is changed is correlated with therotational speed difference between the driving member and the drivenmember.
 8. The gear change control device according to claim 1, incombination with a straddle-type vehicle.
 9. The gear change controldevice according to claim 8, wherein the straddle-type vehicle is amotorcycle.
 10. A method for operating a straddle-type vehicle having aclutch and a transmission driven by respective actuators, comprising:engaging the clutch under a first control routine when the straddle-typevehicle is being started from a stopped condition in which the clutch isdisengaged and the transmission is in gear; determining whether a gearchange command is given to the transmission while the clutch is beingengaged; and when a gear change command is given while the clutch isbeing engaged, disengaging the clutch, changing gears according to thegear change command once the clutch is disengaged, determining anoperating state of the straddle-type vehicle, and, depending upon theoperating state, reengaging the clutch under either the first controlroutine or a second control routine that is different from the firstcontrol routine.
 11. The method of claim 10, wherein the straddle-typevehicle engages the clutch under the first control routine when therotational speed difference between a driving member and a driven memberof the clutch is equal to or greater than a predetermined value, andwherein the straddle-type vehicle engages the clutch under the secondcontrol routine when rotational speed difference between the drivingmember and driven member of the clutch is less than the predeterminedvalue.
 12. The method of claim 10, wherein determining the operatingstate of the straddle-type vehicle comprises determining a rotationalspeed difference between a driving member and a driven member of theclutch.
 13. The method of claim 10, wherein reengaging the clutch undera first control routine comprises changing a position of the clutch as afunction of an engine speed of an engine mounted on the straddle typevehicle.
 14. The method of claim 10, wherein changing a position of theclutch as a function of an engine speed comprises referencing a tablethat correlates clutch position with engine speed.
 15. The method ofclaim 10, further comprising determining a rotational speed differencebetween a driving member and a driven member of the clutch and whereinreengaging the clutch under the second control routine compriseschanging a clutch position at a rate which is determined by thedetermined rotational speed difference between the driving member andthe driven member of the clutch.
 16. The method of claim 15, whereinchanging a clutch position at a rate which is determined by thedetermined rotational speed difference between the driving member andthe driven member of the clutch comprises referencing a table whererates at which the clutch position of the clutch is changed arecorrelated with the rotational speed difference between the drivingmember and the driven member.
 17. A gear change control device for astraddle-type vehicle having a clutch and a transmission, comprising: aclutch actuator configured to engage and disengage the clutch; atransmission actuator configured to change a gear of the transmission;at least one sensor configured to sense an operational condition of thestraddle type vehicle; at least one switch configured to generate a gearchange command; and a controller operatively connected to the clutchactuator, the transmission actuator, the at least one sensor, and the atleast one switch, the controller configured to change gears in responseto the gear change command and during the gear change reengage theclutch under either a first control routine or second, different controlroutine based upon the operational condition of the straddle-typevehicle determined by the at least one sensor; wherein the gear changecommand is given while the clutch is being engaged.
 18. The gear changecontrol device according to claim 17, wherein the controller engages theclutch under the first control routine when the rotational speeddifference between a driving member and a driven member of the clutch isequal to or greater than a predetermined value, and wherein thecontroller engages the clutch under the second control routine when therotational speed difference between the driving member and driven memberof the clutch is less than the predetermined value.
 19. The gear changecontrol device according to claim 17, wherein the operational conditionof the straddle-type vehicle comprises a rotational speed differencebetween a driving member and a driven member of the clutch.
 20. The gearchange control device according to claim 17, wherein the first controlroutine comprises instructions to reengage the clutch by changing aposition of the clutch as a function of an engine speed of an enginemounted on the straddle type vehicle.
 21. The gear change control deviceaccording to claim 17, wherein the second control routine comprisesinstructions to reengage the clutch by changing the clutch position at arate which is determined by a rotational speed difference between adriving member and a driven member of the clutch.
 22. The gear changecontrol device according to claim 17, wherein the controller isconfigured to reengage the clutch under either the first control routineor second, different control routine when the vehicle is in a startingto run condition.
 23. The gear change control device according to claim22, additional comprising an engine speed sensor configured to sense anengine speed of an engine of the straddle-type vehicle and wherein thecontroller is configured to determine if the straddle-type vehicle is inthe starting to run condition, at least in part, on the engine speed.24. The gear change control device according to claim 22, additionalcomprising an accelerator sensor configured to sense an acceleratoropening of an engine of the straddle-type vehicle and wherein thecontroller is configured to determine if the straddle-type vehicle is inthe starting to run condition based, at least in part, on theaccelerator opening.
 25. The gear change control device according toclaim 22, additional comprising an coolant temperature sensor configuredto sense an engine coolant temperature for an engine of thestraddle-type vehicle and wherein the controller is configured todetermine if the straddle-type vehicle is in the starting to runcondition based, at least in part, on the engine coolant temperature.26. A method for operating a straddle-type vehicle having a clutch and atransmission driven by respective actuators, comprising: determiningwhether a gear change command is given to the transmission while theclutch is being engaged; when a gear change command is given while theclutch is being engaged, disengaging the clutch; changing gearsaccording to the gear change command once the clutch is disengaged;determining an operating state of the straddle-type vehicle; anddepending upon the operating state, reengaging the clutch under either afirst control routine or a second control routine that is different fromthe first control routine.
 27. The method according to claim 26, whereinthe straddle-type vehicle engages the clutch under the first controlroutine when the rotational speed difference between a driving memberand a driven member of the clutch is equal to or greater than apredetermined value, and wherein the straddle-type vehicle engages theclutch under the second control routine when rotational speed differencebetween the driving member and driven member of the clutch is less thanthe predetermined value.